Method of marking leathers



Feb. 2, 1932. A. SCHUBERT 1,843,739

y A METHOD 0F MARKING LEATHERS Filed April 29, 1950 PAPER SHEET CARRY/Nq EEE/GN Pff/TED o/v /T w/-rH EN /NK /NcoRPomqT/NG UY/SSOLl/E DYE,

/5 PRESSE-o y ,q PRESS "ro LEETHER l/Y THE PRESE/VCE OF n P/ uREL/TY 0F soL VENTE EOE f/E m/E/EEEn/n ALCOHOL @No @Lv/co1.) ons 0F WHICH H45 H H/GH DEGREE 0E cHP/LLER/TY W/-rH RESPECT To THE PERT/clam? EHTHER HND ONE 0F WHICH [7l/75 N0 ELETER/OUS EFFCT 0N THE I EHTHER.

INVENTOR.

Patented Feb. 2, 1932 UNITED' STATES PATENT ori-"lcs ADOLF SCHUEERT, F MILLBURN, NEW JERSEY, ASSIGNOR TO BARRETT & COMPANY,

i 0F NEWARK, NEW JERSEY, A' CORPORATION OF NEW JERSEY METHOD 0F MARKING LEATHERS vAppnczmon mea April 29,

My inventionrelates to the application to leathers of a process for indelibly marking fibrous articles and materials that I have developed and which is peculiarly suited for applying ornamental markings.

, In this process, the subject matter (letters, numerals, lines, masses of colors, pictures, etc. etc.) is laid down in an ink containing an undissolved dyestuf (or dyestuffs), and then the dyestuff is transferred to the article or material ultimately intended to receive the marking, by contact in the presence of a vtransfer-solvent, so called, which is or includes a solvent for the dyestuff or dyestuffs and which is capable of permeating the vehicle portion of the ink. By my process thus briefly outlined,vit is possible to dye fibrous articles commercially in exact accordance with the original layout of the ink and without noticeable bleeding, lines and color masses being sharply defined and original color gradations being carried over into the reproduction on the article. Sheets of paper, cloth, or the like,'on' which the subject matter is printed and from which the transfer is made,

are called transfer sheets.

Hereinafter I refer vprincipally to the use of but one dye (singular number) in any ink; it will be understood however that-an w ink may incorporate more than one dye.

In applying'my process to the ornamenting of leather, I use a dye capable of dyeing leathers or skins, as the dyestuffs in the ink, and I have found it highly desirable that the solvent for the dye, used in transferring the dye to the leather, be a substance that has a high degree of capillarity with respect to the leather to be marked, and the particular kind of leather to be marked; that is lto say, I have 40 found that the dye solvent should be a substance Which penetrates and diffuses through the leather rapidly. Despite the fact that'a high rate of""diffusion of the dye solvent would seem to promote bleeding of the color, such find is not the case.' As hereinafter mentioned again, I employ as the dye solvent a substance or substances from which the dye becomes substantially absorbed as the dye approaches and becomes aflixed to the leather fibers; it may be that this characteristic of to the particular kind of leather to be marked.

to leathers by my process.y

1930. serial No. 448,434.

the dye solvent I employ permits the use of high capillarity solvents without bleeding.

It will be observed that the capillarity here referred to is to be measured with respect The capillarity of various dye solvents varies 0 5 with the leather. A convenient method of measuring the relative capillarity is to take a number o f strips of the leather, and, suspending them vertically, immerse one end of each in one of the solvents otherwise deemed suitable for the process (immersing them to equal depths) fand then note the height to which the various solvents rise in the strips in some convenient short unit of time, say 5 one minute. Using this method, I have found that in a vegetabletanned leather, a'certain denatured ethyl alcohol rose five-sixteenths of an inch in one minute, acetone twelve sixteenths, and methylene glycol eight sixfu teenths of an inch; in a chrome tanned leather and the ethyl alcohol rose twelve sixteenths of an inch, acetone fifteen sixteenths, and methylene glycol nine sixteenths of an inch.

I chose these three substances, because of la their relatively high capillarity for these two leathers, and because the alcohols, acetone and the glycols are solvents for a large range of dyes suitable for the ornamenting of leather, and otherwise are suitable for use in my transfer process as applied to leather.

It would seem from these results that the acetone is most suitable for both the chosen chrome tanned and the vchosen vegetable tanned leather, and should be used; such es would be the case cxcept for the fact that acetone is expensive. I would use therefore, by preference, the ethyl alcohol for this chrome rtanned leather, and its capillarity is quite sufiicient for good results. For the chosen Vegetable tanned leather, the glycol is next to acetone in capillarity, and therefore glycols would seem to be yindicated for the vegetable tanned leathers. However, the glycols' are also relatively expensive. On 95 the whole therefore. I believe that the alcohols, and particularly ethyl alcohol, are-the most suitable solvents for transferring dyes v Ethyl'alcohol however, has a deleterious m0 and ethylene glycol.

effect on vegetable tanned leathers and Yon some chrome tanned leathers; lit tends to extract the tannin. In my work however, I have found that the solvent for the dye need not ,be limited to a single substance, but that two lor more solvents for the same dye may be used together; furthermore (as I have) pointed out in my copending application for patent Serial No. 448,435, filed April 29,

l0 1930) I 'have found that Where a desirable by diluting, as itrvere, the desirable dye solvent with a substance which has no delel terious efect on the leather. Consequently,`

according to my present invention, for transferring to those leathers for which the pre ferred dyesolvent alone is unsuitable, I pro pose to use two or more solvents for-the dye, one the solvent preferred without reference toits efecton the leather-and another (or others) a solvent for the dye which has no deleterious efl'ect on the leather; preferably a mixture of ethyl alcohol and a glycol; still more preferably, a mixture of ethyl alcohol A mixture \of about equal parts of the latter is usually quite satisfactory.

In applying my present invention therefore: I use as the dyestu' in the ink'a dye capable of directly dyeing the leather to be worked upon (using the term .dye.with the 5 meaning hereinafter given to it), and usually an alcohol-soluble dye. With the chosen dye I mix a vehicle to suit the particular conditions under which the subject matter is laid down for transfer of the dye to the leather, as suiting the particular printing process vselected for printing on paper sheets; thus for printing on sheets of paper, cloth or other similar light thin flexible materials, the vehicle material is solchocsen that the ink resulting from the mixture has that viscosity, tacky or greasy nature or whatever other characteristics may be required of the ink used in thevparticular printing process emr ployed for` laying down the ink on the sheet. Furthermore I choose for the vehicle a substance or substances that will remain on such transfer sheets until the transfers are made to the leather; I believe that the presence ofthe vehicle at the time the transfer is made helps to confine the dye to its intended boundaries. The dye is not to be held in the vehicle in solution however, but in a solid state; in sus ensionr as it were. If the dyestu` -is solu le in the vehicle bleeding may take place in the transfer sheet and this result in blurred outlines and poor color gradations in the reproduction on the leather. Furthermore for certain colors I have seemed to indit possible to get suficient dye into the veein dissolved form to give the desired color intensity in the reproduction. Hence I `use as the vehicle portion of the ink (including in that term everything in the'ink excepting the dye), a material or materials in which the dye 'f is substantially insoluble. Conceivably the dye may be introduced into the vehicle initially in the form of a solution if desired, provided the solvent is evaporated for example, or if the dye is precipitated or is otherwise restored to or produced in a solid state prior to printing on the5 transfer sheet base; at the time of the print-4 ing of the transfer sheet however, substantially all the dye should be in an undissolved state, and it should remain in this solid state With such an ink I usually print up a stock of transfer sheets at one time; that is to say, I print the subject matter ogn such a quanl tity of sheetsof paper, cloth or other relatively light, thin, flexible material as may correspond to the number of skins or pieces of leather'to be marked, or as may be needed for some time to come. Preferably I use a fibrous material for these transfer sheet basesf because of the permeability of the librous materials. Newsprint paper is'suitable and. usually lgives better results than a heavily sized paper. The stock of transfer sheets can be used as needed| so long as the vehicle remains on the transfer sheets and remains permeableY to the dye solvent, or remains in -a condition where it can be` made permeable vto the dye solvent. f

To make a transfer or print on a leather the ink is brought into contact with the leather, as by pressing one of the transfer sheets smoothly to the leather, inked'face to the leather, in the presence of a solvent or solvents of the dye of relatively high capillarity with respect to the particular leather being treated, as before explained. In addition to being a solvent for the dye,.the dye solvent or vsolvents must be readily permeable into '(capable of ventering readily) the vehicle part of the ink arid capable of carrying dye, or the needed dyeing principle, from well within the vehicle into dyeing relation with the fibers of the leather. In order that the dye solvent may enter the vehicles, the materials composing the vehicle and the dye solvent (or one of the latter) may be so chosen with respect to each other that the dye solvent has this characteristic of and by itself; for example, the dye solvent may be asolvent for the" inkvehicle. In the alternative, an additional substance may be employed to give the dye solvent access into the vehicle; the latter is the subject of a copending application of mine; the additional substance, say a solvent for the vehicle (the latter being substantially insoluble in the dye solvent), can be applied separately to the ink, or as a mixture with the dye solvent or solvents. Where the dye appears in the ink as a compound needing to be broken. up, or which can be broken up, before its action on' the fibers is accomplished (for example where the dye is in the form of a lake) the dye solvent can be selected for its ability to break up the compound, as well as dissolve the dye; or in the alternative an additional substance may be used along with the dye solvent to break up'the compound; the dye solvent need not then be a solvent for the dye compound found in the ink; it only need be a solvent for the dye proper, or the essential principle needed for dyeing the leather. As before indicated, also, the dye solvent or solvents of high capillarity is or are chosen from substances in which the dye becomes relatively insoluble as the dye comes into dyeing relation to the leather fibers and becomes affixed thereto. And further of course the dye solvent (or. dye solvents) is (or are) chosen from substances that do not attack and modify the leather to a material degree, unless contrary precautions are taken. Thecapillarity of a desired solvent may be modified as necessary or desirable by the addition thereto of another solvent for the same dye; or two or more solvents may be employed as economy and operating conditions may dictate. For example, when an economically desirable dye solvent has a deleterious effect on the particular leather to be l0 .7marked, another solvent for the dye not actling deleteriously on the leather may be used Ialong with the first to avoid the delecterious action; a glycol is preferredr as the non-deleterious dye solvent in such a case. For general use I prefer the alcohols as the dye solvent. and particularly ethyl alcohol, denatured or not; and I prefer a mixture of ethyl alcohol and ethylene glycol where the leather worked upon is deleteriouslyaffected by the alcohol alone. Usually I apply the dye solvent to the leather, either by spraying or dipping immediately before the transfer, and apply the transfer sheet dry to the wettedleather; I regard this practice as highly desirable.

When two or more solvents are used, and also, when an additional substance is to be used at the time of lmaking the transfer, such, for example, as a substance to give the dye solvent or'solvents access into a vehicle into which it or they are otherwise substantially impermeable, I usually mix the whole and apply the mixture in the same way. Usually too I press the transfer sheet to the leather with considerable pressure, as in a press; I have used up to 300 pounds per square inch. This is not to be understood to indicate however that such high pressures as this are always necessary. Where heat does not deleteriously affect the leather, heat may be used simultaneously, as by passing steam through pipes provided in the plates of the press; heat is not altogether 'an essential however. The transfer of dye to the leather takes place rather quickly, at least. under high pressure, the transfer being produced in from a fraction of a minute to two minutes. At the same time the length of time the transfer sheet is left in contact with the leather is not critical; for example, without heat .I haveleft a transfer sheet in contact with a leather, under pressure, for as much as five minutes without producing noticeable bleeding or blurring. When a transfer has been accomplished, the transfer sheet is peeled olf the leather of course. Preferably I employ dye solvents that are also volatile, so that they are readily removed or escape naturally from the leather by evaporation after having performed their functions. t

It will now be apparent that various kinds of dyes can be used in the ink, and the exact nature of the dye employed is not material to my invention, excepting only that it bea dye capable of dyeing'the leather, as the term ldyeing is used in the dyeing art, and not a mere staining, or a mere fixing of pigment to the leather by the vehicle of the ink after the manner of printing. The dye may be a substance capable as a whole of dyeing the leather. Or it may be a comppund, such as a lake, from which the dyeing principle is to be extracted. For developed colors and other dyes acting in analogous ways, all the constituents may be incorporated in the ink when the conditions are suitable, or only a part of the constituents may appear in the ink, and when necessarythe remainder apv plied directly to the leather either before or after the transferring operation. In general, the various forms which the dye may assume will be understood by those skilled in the art, who will understand also the various manners in which the leather may be treated either before or after the transferring is done, or both before and after, either to prepare the leather, for cleaning, te brighten the colors, etc. etc.

, As a specific example of my process incorporating the present invention: In finely powdered form,l luxol black is ground into a rosin oil varnish, and the mixture thickened or thinned with otherwise inert substances, to such a consistency that the resulting dyevehicle mixture has that consistency required for the/operation of printing the transfer sheets. The rosin oil referred to is a. distillate of colophony, as will be understood. The

ratio of the dye, luxol black, to the vehicle is found by trial, that ratio being used which gives the desired color.. strength ortinctorial value on'the leather. l have used ratios from` one part of the black to twelve parts of the vehicle (for a'shade of grey) up to one part of the black to two parts of vehicle (Where a 1.5 Afull shade of black Was obtained) the measurements were by Weight. With the ink thus` 'formed the design or ornamental matter is printed on sheets of such paper as is'used for newsprint, using blocks or rolls etched or engraved or otherwise marked in accordance with the desired design, as the printing proc- -ess may demand. Usually I print up a stock of these transfer sheets at once, since this ink willv remain permeable to the dye solvents Thereafter specified for quite a While. When, it comes time to make a transfer to, say, a'

vegetable tanned leather, the leather is -sprayed With or dipped into a mixture of etnyl alcohol and ethylene glycol in about ..20 equal parts, and immediately thereafter one of the transfer sheets is laid onthe leather, 'inked face to the leather, and the two pressed momentarily in a press. The leather usually being of different thicknesses throughout its f2.5 extent, l lemploy considerable pressure to evenly and uniformly contact the transfer sheet with the leather; to aid the action a rather soft pad may be imposed between the transfer sheet and the adjacent plate of the A 0 press. The rosin oil vehicle of the ink being soluble in the ethyl alcohol, the dye solvents,

`\ ethyl alcohol and ethylene glycl,penetrate Well. into the ink immediately upon this contact, dissolve more or less of the dye, and

carry the same into the midst of the fibers of the'leather, to which it thereupon becomes affixed; that is toA say, dyes the leather. After pressing the transfer sheet to the leather for a moment therefore, vthe twol are taken from I .40 the press, and the transfer sheet is peeled off. vIt will be understood from the foregoingv that my invention is not limited to the details bf the foregoing description, except as appears hereinafter in the/claims'.

. 1. The method of lmaking markings on leather which consists in producing the sub- `ject matter in anink incorporating a dye capable of dyeing the leather and a vehicle suiting the particular process by which the ink is laid down, and in which vehicle the.

dye is substantially insoluble, and pressing y the subject matter, formed by such ink, to the leather in the presence of a solvent for i the dye capable f carrying dye from the ink incorporating a dye capable o f dyeing the leather and vehicle material sulting the particular printing process by which the printing on to the transfer s eet bases is done, and in which the dye is substantiallyv fibers, and 4which-has a degree of capillarity,

with respect to the particular leather being marked, of the order indicated.

32 The method of making 'markings on leather which consists in printing the subject matter on transfer sheet bases with an ink incorporating a dye capable of dyeing the leather and vehicle material suiting the particular printing process by which the printing on to the transfer sheet bases is done, and in which the dye is substantially insoluble, and pressing, While the vehicle is still present on the `transfer sheets, the transf fer sheets to the leather lin the presence of a plurality o-f solvents for the dye capable of carrying dye from the ink into the midst of the fibers of the leather, from at least one of which solvents the dye becomes substantially absorbedas the dye approaches and becomes affixed to the leather fibers, and of which sol- Vents one has a deleterious effect on the leather and another does not deleteriously 'printing onto the transfer sheet bases is done, and in which the dye issubstantially insoluble, and pressing, While the vehicle is still present on the transfer sheets, the transfer sheets to the leather in the presence of a plurality of solvents for the dye capable of carrying dye from the ink into the midst of the fibers of the leather, from which solvents the dye becomes substantially` absorbed as the dye approaches and becomes affixed to) the leather'fibers, and of which dye solvents at least one has a high degree ofcapillarity i with respect to the particular leather being marked.

5. The methodof making markings on leather` which consists in printing the subject matter on transfer sheet bases With an ink incorporating a dye capable of dyeing the leather and vehiclematerial suiting the particularI printing process .by which the rinting on to the transfer sheet bases -is one, and in which the dye is substantially,

insolublefforming a mixture of plurality of solvents for the dye capable of carrying dyev ing al deleterious effect on the leather, and

. pressing, While the vehicle is still present on the transfer sheets, the transfer sheets to the leather in the presence of said preformed 'mixture 6. The method of making markings on,

leather which consists in printing the subject matter on transfer `sheet bases With an ink incorporating a dye capable of dyeing the leather and vehicle material suiting the particular printing process by which the printing on to the transfer sheet basesis done, and in which the dye is substantially insoluble, .and pressing, While the vehicle is still present on the transfer sheets, the transfer sheets to the leather in the presence of a plurality of solvents for the dye capable of carrying dye from the ink into the midst of the fibers of the leather, from which solvents the dye becomes substantially absorbed as the dye approaches and becomes afiixed to the leather fibers, and which have different degrees of capillarity with respect to the particular leather being marked, the said solvents as a mixture having a-high degree of capilla-rity with respect to the particular leather being marked.

l7. The method of making markings on leather which consists in printing the subject matter on transfer sheet bases with an ink incorporating a dye capable of dyeing the leather and vehicle material sui-ting the particular printing process by which the printing on to the transfer sheet bases is done, and in which they dye is substantially insoluble, and pressing, While the vehicle is still present on the transfer sheets, the transfer sheets to the leather in the presence of a glycol and in the presence of a solvent for the dye capable of carrying dye from the ink into the midstcf the fibers of the leather, from which solvent the dye becomes substantially absorbed as the dye approaches and becomes affixed to the leather fibers, andv Which tends to have a deleterious effect on the leather.

"printing on tothe transfer sheet bases is done, and inv which the dye is substantially insoluble, and pressing, While the vehicle is still present on the transfer sheets, the transfer sheets to the leather in the presence of an alcohol..

9. The method'of making markings on leather which consists in printingrthe subject matter on transfer sheet bases with an ink incorporating a dye capable of dyeing the leather and vehicle material'suiting the particular printing process by which the printing on to the-transfer sheet bases is done, and in which the dye is substantially insoluble,

and pressing, While the vehicle is still present on the transfer sheets, the transfer sheets, the transfer sheets to the leather in the presence of ethyl alcohol.

10.' The method of making markings on 'leather which consists in printing the subject matter on transfer sheet bases with an ink incorporating a dye capable of dyeing the leather and vehicle material suiting the particular printing process by which the printing on to the transfer sheet bases is done, and in which the dye is substantially insoluble, and pressing, While the vehicle is still present on the transfer sheets, the transfer sheets to the leather in the presence of thyl alcohol and another solvent for the' 11. The method of making markings on leather which consists in printing the sub` ject matter on transfer sheet bases with an ink incorporating a dye capable of dyeing the leather and vehiclematerial suiting the particular printing process by Which the printing on to the transfer sheet bases is done, and in which the dye is substantially insoluble, and pressing, While the vehicle is still present on the transfer sheets, the transfer 'sheets to the leather in the presence of ethyl alcohol and a glycol.

12. The method of making markings on leather which consists in printing the subject matter on transfer sheetbases With an ink incorporating a` dye capable of dyeing the specification. y

i ADOLF SCHUBERT. y 

